Breadth - Structural Engineering Flashcards
what is a tributary area?
a tributary area is a smaller piece of a girder or panel
what is a windload?
it is a load applied to vertical surfaces. for leeway loads it will act upwards
what is a snow load?
a snow load is a load that is a uniformly distributed load and a vertical load
what is ASD?
ASD is the allowable stress design method for loads and they are simply added together
what is the LRFD?
the LRFD is loads that have factors that need to be multiplied
what makes a stable structure?
it is a structure that may bend or deflect and should not move
what are common internal instability structures?
3 hinges in a row in a beam or a frame, parallel or concurrent forces in a determinant truss, and and structure that is not satisfied
what values do you need to know in order to find determinancy?
you need to know the number of members, joints, reactions, and connections
what determines a joint?
a joint in a stability problem is where reactions happen
what are the 2 different methods to find members and forces within a truss?
you can find the forces of trusses by method of joints or cutting the truss in half
what are zero force members?
zero force members are members in the truss that have no force in them
what are the rules of the zero force members?
if only 2 members are connected to a joint, with no external force then both members are F=0, if 3 members are connected to a joint, 2 collinear and 1 non linear then the colinear members are F=0, AND if FOUR members are connected at a joint w/o external force and collinear in pairs then the forces in collinear members are equal
what is a compound truss?
2 simple trusses connected by 3 non parallel bars
what are building frames?
they are like trusses except they are indeterminate and are like braced structures
what is the hack to solving frame problems?
because frames are braced and resist tension so you can remove a brace and find the forces since that allows it to become determinant
what does the value of zero in shear diagram mean?
where shear is zero on a diagram then that means that at that point the greatest moment occurs
when shear is linear what does that say about moment diagram?
the moment diagram will be parabolic
what is the shear stress formula?
shear stress is t=v/a
v = shear force and A = area
what is poisson’s ratio?
poissons ratio is a formula used to find the axial force in the x-direction
v= - (strain y direction) / (strain x direction)
where is the neutral axis?
the neutral axis is located at the center of the section
what is the first step when dealing with a nonsymmetric shape?
find the neutral axis by breaking down the shape and using sum of y = (sum y*A)/sum of A
what happens when a shape is not located on the main axis’?
remember to use the parallel axis theorem
what is the formula for the max moment for a distributed load on a beam?
w=wl^2/8
what is the formula for the max moment for a point load on a beam?
w=p*L/4
what is Q in shear diagrams
Q=y (bar)*A
Q is the area at a certain section in the beam
what is shear flow?
shear flow is needed to calculate shear stress. this can also be used to find the nails and the connectors
what can nails/studs/glue do along beams?
nails can resist the shear stress that happens along the beam.
what is the formula for max shear?
3V / 2A
3/2* average shear
the maximum torsion occurs where along a circular shaft?
the maximum torsion occurs at the outer most radius of the shaft